Migration resistant embolic filter

ABSTRACT

An embolic filter is disclosed and can include a head. A plurality of bent legs can extend from the head. Each bent leg can be configured to engage an inner wall of a vein and prevent the embolic filter from migrating in a cranial direction. A plurality of straight legs can also extend from the head. Each straight leg can be configured to prevent the embolic filter from migrating in a caudal direction.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to surgical devices. Morespecifically, the present disclosure relates to embolic filters.

BACKGROUND

A pulmonary embolism (PE) is a blockage of the pulmonary artery, or abranch of the pulmonary artery, by a blood clot, fat, air, a clump oftumor cells, or other embolus. The most common form of pulmonaryembolism is a thromboembolism. A thromboembolism can occur when a venousthrombus, i.e., a blood clot, forms in a patient, becomes dislodged fromthe formation site, travels to the pulmonary artery, and becomesembolized in the pulmonary artery. When the blood clot becomes embolizedwithin the pulmonary artery and blocks the arterial blood supply to oneof the patient's lungs, the patient can suffer symptoms that includedifficult breathing, pain during breathing, and circulatory instability.Further, the pulmonary embolism can result in death of the patient.

Commons sources of embolism are proximal leg deep venous thrombosis(DVTs) and pelvic vein thromboses. Any risk factor for DVT can alsoincrease the risk that the venous clot will dislodge and migrate to thelung circulation. One major cause of the development of thrombosisincludes alterations in blood flow. Alterations in blood flow can be dueto immobilization after surgery, immobilization after injury, andimmobilization due to long-distance air travel. Alterations in bloodflow can also be due to pregnancy and obesity.

A common treatment to prevent pulmonary embolism includes anticoagulanttherapy. For example, heparin, low molecular weight heparins (e.g.,enoxaparin and dalteparin), or fondaparinux can be administeredinitially, while warfarin therapy is commenced. Typically, warfarintherapy can last three to six months. However, if a patient hasexperienced previous DVTs or PEs, warfarin therapy can last for theremaining life of the patient.

If anticoagulant therapy is contraindicated, ineffective, or both, anembolic filter can be implanted within the inferior vena cava of thepatient. An embolic filter, i.e., an inferior vena cava filter, is avascular filter that can be implanted within the inferior vena cava of apatient to prevent PEs from occurring within the patient. The embolicfilter can trap embolus and prevent the embolus from travelling thepulmonary artery.

An embolic filter can be permanent or temporary. Further, an embolicfilter can be placed endovascularly, i.e., the embolic filter can beinserted into the inferior vena cava via the blood vessels of thepatient. Modern filters have the capability to be compressed intorelatively thin diameter catheters. Further, modern filters can beplaced via the femoral vein, the jugular vein, or via the arm veins. Thechoice of route for installing the embolic filter can depend on theamount of blood clot, the location of the blot clot within the venoussystem, or a combination thereof.

The blood clot can be located using magnetic resonance imaging (MRI).Further, the filter can be placed using a filter delivery system thatincludes a catheter. The catheter can be guided into the IVC usingfluoroscopy. Then, the filter can be pushed from the catheter anddeployed into the desired location within the IVC. Typically, a filtercan be anchored to prevent migration through the IVC.

Accordingly, there is a need for an improved embolic filter that hasdesired functionality and stability.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of a portion of a cardiovascular system;

FIG. 2 is a plan view of a filter delivery device;

FIG. 3 is a plan view of an embolic filter in a collapsed configuration;

FIG. 4 is a plan view of the embolic filter in an expandedconfiguration;

FIG. 5 is a detailed view of the embolic filter taken at circle 5 inFIG. 4;

FIG. 6 is a detailed view of the embolic filter taken at circle 6 inFIG. 4;

FIG. 7 is a plan view of a foot of the embolic filter;

FIG. 8 is a plan view of the foot engaged with the inner wall of a vein;

FIG. 9 is a cross-section view of the embolic filter taken at line 8-8in FIG. 4; and

FIG. 10 is an alternative cross-section view of the embolic filter.

DETAILED DESCRIPTION OF THE DRAWINGS

An embolic filter is disclosed and can include a head. A plurality ofbent legs can extend from the head. Each bent leg can be configured toengage an inner wall of a vein and prevent the embolic filter frommigrating in a cranial direction. A plurality of straight legs can alsoextend from the head. Each straight leg can be configured to prevent theembolic filter from migrating in a caudal direction.

In another embodiment, an embolic filter is disclosed and can include ahead. A first plurality of legs can extend from the head. Each of thefirst plurality of legs can be configured to engage an inner wall of avein and prevent the embolic filter from migrating in a cranialdirection. Also, each of the first plurality of legs can include a firstleg diameter. The embolic filter can also include a second plurality oflegs that can extend from the head. Each of the second plurality of legscan be configured to prevent the embolic filter from migrating in acaudal direction and each of the second plurality of legs can have asecond leg diameter that is at least 1.2 times greater than the firstleg diameter.

In yet another embodiment, an embolic filter is disclosed and caninclude a head. A first bent arm, a second bent arm, a third bent arm, afourth bent arm, a fifth bent arm, and a sixth bent arm can extend fromthe head. Each bent arm can include a proximal end and a bent armdiameter. Moreover, a first bent leg, a second bent leg, and a thirdbent leg can extend from the head. Each bent leg can include a proximalend and a bent leg diameter that is substantially equal to the bent armdiameter. In this embodiment, a first straight leg, a second straightleg, and a third straight leg can extend from the head. Each straightleg has a proximal end and a straight leg diameter that is at least 1.2times greater than the bent leg diameter or the bent arm diameter.

Description of the Relevant Anatomy

Referring to FIG. 1, a portion of a cardiovascular system is shown andis generally designated 100. As shown, the system can include a heart102. A superior vena cava 104 can communicate with the heart 102.Specifically, the superior vena cava 104 can provide blood flow into aright atrium 106 of the heart 102 from the generally upper portion of ahuman body. As shown, an inferior vena cava 108 can also communicatewith the heart. The inferior vena cava 108 can also provide blood flowinto the right atrium 106 of the heart 102 from the lower portion of thecardiovascular system. FIG. 1 also shows a right subclavian vein 110, aleft subclavian vein 112, and a jugular vein 114 that can communicatewith the superior vena cava 104.

Description of a Filter Delivery Device

FIG. 2 illustrates a filter delivery device, designated 200. As shown,the filter delivery device can include a body 202. The body 202 of thefilter delivery device 200 can be generally cylindrical and hollow.Also, the body 202 of the filter delivery device 200 can include aproximal end 204 and a distal end 206. A side port 208 can be formed inthe body 202 of the filter delivery device 200 between the proximal end204 of the body 202 and the distal end of the body 202. A saline dripinfusion set 210 can be connected to the side port 208 of the body 202.In a particular embodiment, the saline drip infusion set 210 can be usedto deliver saline to the patient during the delivery and deployment ofan embolic filter using the filter delivery device 200.

As depicted in FIG. 2, an adapter 212 can be connected to the proximalend 204 of the body 202 of the filter delivery device 200. Also, afilter storage tube adapter 214 can be connected to the distal end 206of the body of the filter delivery device 200. FIG. 2 shows that thefilter delivery device 200 can also include a filter storage tube 216.The filter storage tube 216 can be hollow and generally cylindrical.Further, the filter storage tube 216 can include a proximal end 218 anda distal end 220. As shown, the proximal end 218 of the filter storagetube 216 can be coupled to the filter storage tube adapter 214. Anintroducer catheter 222 can be connected to the distal end 220 of thefilter storage tube 216.

In a particular embodiment, an embolic filter 224 can be stored withinthe filter storage tube 216. As shown, the embolic filter 224 can beformed into a collapsed configuration and installed within the filterstorage tube 216. The embolic filter 218 can be the embolic filterdescribed below. Further, the embolic filter 218 can be made from ashape memory material. The shape memory material can be a shape memorypolymer. Further, the shape memory material can be a shape memory metal.The shape memory metal can be a nickel titanium alloy such as nitinol.

FIG. 2 shows that a pusher wire 226 can be slidably disposed within thebody 202 of the filter delivery device 200. The pusher wire 226 can beformed from an extremely flexible metal alloy, e.g., a nickel titaniumalloy. The nickel titanium alloy can include nitinol. Further, thepusher wire 226 can extend through the body 202 of the filter deliverydevice 200 and into the filter storage tube 216. The pusher wire 226 caninclude a proximal end 228 and a distal end 230. A pusher wire handle232 can be attached to, or otherwise formed with, the proximal end 228of the pusher wire 226. The distal end 230 of the pusher wire 226 canextend into the filter storage tube 216 attached to the body 202.Further, the distal end 230 of the pusher wire 226 can include a pusherhead 234 that can contact the embolic filter 218.

During installation of the embolic filter, the installation catheter 222can be threaded into the cardiovascular system of a patient, e.g., thecardiovascular system 100 described above, in order to deliver anddeploy the embolic filter to the desired location with the patient. Forexample, the installation catheter 222 can be threaded through thefemoral artery into the inferior vena cava of the patient. A distal endof the installation catheter 222 can include a pair of radiopaque bandsspaced a predetermined distance apart. Using fluoroscopy, the radiopaquebands can indicate when the distal end of the installation catheter 222is located at or near the desired location within the inferior venacava.

When the distal end of the installation catheter 222 is in the desiredlocation within the inferior vena cava, the pusher wire 226 can be movedthrough the body 202 of the filter delivery device 200, through thefilter storage tube 216 and into the installation catheter 222. As thepusher wire 226 is pushed through the filter storage tube 216, theembolic filter 224 is pushed from within the filter storage tube 216into the installation catheter 222. The embolic filter 224 can be pushedthrough the installation catheter 222 until it is expelled from thedistal end of the installation catheter 222 into the inferior vena cava.Upon exiting the installation catheter 222, the embolic filter 224 canbe warmed by the body temperature of the patient. When the embolicfilter 224 reaches approximately thirty-seven degrees Celsius (37° C.),e.g., normal body temperature, the embolic filter 224 can move from thecollapsed configuration to an expanded configuration within the inferiorvena cava. Thereafter, the installation catheter 222 can be withdrawnfrom the patient.

Description of an Embolic Filter

Referring now to FIG. 3 and FIG. 4, an embolic filter is shown and isgenerally designated 300. As depicted in FIG. 4, the embolic filter 300can include a head 302. The head 302 can be generally cylindrical andhollow. Further, the head 302 can have a proximal end 304 and a distalend 306. The proximal end 304 of the head 302 can be closed and thedistal end 306 of the head 302 can be open. As such, the head 302 can begenerally shaped like a test tube.

As indicated in FIG. 4, a first bent arm 308 can extend from the distalend 306 of the head 302. A second bent arm 310 can extend from thedistal end 306 head 302. A third bent arm 312 can extend from the distalend 306 of the head 302. A fourth bent arm 314 can extend from thedistal end 306 of the head 302. A fifth bent arm 316 can extend from thedistal end 306 of the head 302. Further, a sixth bent arm 318 can extendfrom the distal end 306 of the head 302. Each bent arm 308, 310, 312,314, 316, 318 can include a first portion 320 and a second portion 322.In the deployed, expanded configuration, shown in FIG. 4, the firstportion 320 of each bent arm 308, 310, 312, 314, 316, 318 can extendfrom the head at an angle with respect to a longitudinal axis 324 toform a primary bent arm angle 326.

The primary bent arm angle 326 can be approximately forty-five degrees(45°). In another embodiment, the primary bent arm angle 326 can beapproximately fifty degrees (50°). In yet another embodiment, theprimary bent arm angle 326 can be approximately fifty-five degrees(55°). In still another embodiment, the primary bent arm angle 326 canbe approximately sixty degrees (60°). In another embodiment, the primarybent arm angle 326 can be approximately sixty-five degrees (65°).

The second portion 322 can be angled with respect to the first portion320 to form a secondary bent arm angle 328. In particular, the secondportion 322 can be angled inward with respect to the first portion 320,e.g., toward the longitudinal axis 324 of the embolic filter 300.

In a particular embodiment, the secondary bent arm angle 328 can beapproximately twenty degrees (20°). In another embodiment, the secondarybent arm angle 328 can be approximately twenty-five degrees (25°). Inyet another embodiment, the secondary bent arm angle 328 can beapproximately thirty degrees (30°). In still another embodiment, thesecondary bent arm angle 328 can be approximately thirty-five degrees(35°). In another embodiment, the secondary bent arm angle 328 can beapproximately forty degrees (40°). In yet still another embodiment, thesecondary bent arm angle 328 can be approximately forty-five degrees(45°).

In a particular embodiment, each bent arm 308, 310, 312, 314, 316, 318is movable between a straight configuration, shown in FIG. 3, and anangled configuration, shown in FIG. 4. When the embolic filter 300 is inthe pre-deployed, collapsed configuration, shown in FIG. 3, the bentarms 308, 310, 312, 314, 316, 318 are substantially straight andsubstantially parallel to the longitudinal axis 324 of the embolicfilter. When the embolic filter 300 moves to the deployed, expandedconfiguration, shown in FIG. 4, the bent arms 308, 310, 312, 314, 316,318 can move to the angled and bent configuration shown in FIG. 4.

As further illustrated in FIG. 3, a first bent leg 330 can extend fromthe head 302. A second bent leg 332 can extend from the head 302.Moreover, a third bent leg 334 can extend from the head 302. Each bentleg 330, 332, 334 can include a substantially straight first portion 336and a substantially straight second portion 338. The first portion 336of each bent leg 330, 332, 334 can extend from the head 302 at an anglewith respect to the longitudinal axis 324 to form a primary bent legangle 340.

In a particular embodiment, the primary bent leg angle 340 can beapproximately twenty degrees (20°). In another embodiment, the primarybent leg angle 340 can be approximately twenty-five degrees (25°). Inyet another embodiment, the primary bent leg angle 340 can beapproximately thirty degrees (30°). In still another embodiment, theprimary bent leg angle 340 can be approximately thirty-five degrees(35°). In another embodiment, the primary bent leg angle 340 can beapproximately forty degrees (40°). In yet still another embodiment, theprimary bent leg angle 340 can be approximately forty-five degrees(45°).

The second portion 338 of each bent leg 330, 332, 334 can extend beangled with respect to the first portion 336 in order to form asecondary bent leg angle 342. Specifically, the second portion 338 canbe angled outward relative to the first portion 336, e.g., away from thelongitudinal axis 324 of the embolic filter 300.

In a particular embodiment, the secondary bent leg angle 342 isapproximately five degrees (5°). In another embodiment, the secondarybent leg angle 342 is approximately ten degrees (10°). In still anotherembodiment, the secondary bent leg angle 342 is approximately fifteendegrees (15°). In yet another embodiment, the secondary bent leg angle342 is approximately twenty degrees (20°). In another embodiment, thesecondary bent leg angle 342 is approximately twenty-five degrees (25°).

In a particular embodiment, each bent leg 330, 332, 334 is movablebetween a straight configuration, shown in FIG. 3, and an angled andbent configuration, shown in FIG. 4. When the embolic filter 300 is inthe pre-deployed, collapsed configuration, shown in FIG. 3, the bentlegs 330, 332, 334 are substantially straight and substantially parallelto the longitudinal axis 324 of the embolic filter. When the embolicfilter 300 moves to the deployed, expanded configuration, shown in FIG.4, the bent legs 330, 332, 334 move to the angled and bent configurationshown in FIG. 4.

Each bent leg 330, 332, 334 can also include a foot 344. As shown inFIG. 5, the foot 344 of each bent leg 330, 332, 334 can be curved toform a hook. Each hook can also form a barb. In particular each foot 344can move from a straight configuration, shown in FIG. 3, to a curvedconfiguration, shown in FIG. 4 and FIG. 5. As such, when the embolicfilter 300 is in the collapsed configuration shown in FIG. 3, the feet344 of the bent legs 330, 332, 334 are straight. When the embolic filter300 moves to the expanded configuration, the feet 344 are bent. Further,when the feet 344 are bent, the feet 344 can extend into and engage theinner wall of a vein in which the embolic filter is installed. The feet344 can substantially prevent cranial migration of the embolic filter300. In other words, the feet 344 can engage the inner wall of the veinand substantially prevent the embolic filter 300 from moving upstream ina cranial direction within the vein due to blood flow through theembolic filter 300.

FIG. 4 indicates that the embolic filter 300 can include a firststraight leg 350, a second straight leg 352, and a third straight leg354. Each straight leg 350, 352, 354 can extend from the distal end 306of the head 302. In the expanded configuration, in particular, eachstraight leg 350, 352, 354 can extend from the head 302 at an angle withrespect to the longitudinal axis 324 to form a primary straight legangle 356.

In a particular embodiment, the primary straight leg angle 356 can beapproximately twenty degrees (20°). In another embodiment, the primarystraight leg angle 356 can be approximately twenty-five degrees (25°).In yet another embodiment, the primary straight leg angle 356 can beapproximately thirty degrees (30°). In still another embodiment, theprimary straight leg angle 356 can be approximately thirty-five degrees(35°). In another embodiment, the primary straight leg angle 356 can beapproximately forty degrees (40°). In yet still another embodiment, theprimary straight leg angle 356 can be approximately forty-five degrees(45°).

Each straight leg 350, 352, 354 can include a distal end 358 that isconfigured to engage the inner wall of the vein in which the embolicfilter 300 is installed. In particular, as shown in FIG. 6, the distalend 358 of each straight leg 350, 352, 354 can include a vein engagementface 360 that is configured to engage the inner wall of a vein, as shownin FIG. 8. Further, each vein engagement face 360 can be angled withrespect to a longitudinal axis 362 defined by each straight leg 350,352, 354 in order to establish a vein engagement face angle 364.

In a particular embodiment, the vein engagement face angle 364 can beninety degrees (90°). In another embodiment, the vein engagement faceangle 364 can be ninety-five degrees (95°). In still another embodiment,the vein engagement face angle 364 can be one hundred degrees (100°). Inanother embodiment, the vein engagement face angle 364 can be onehundred five degrees (105°). In yet another embodiment, the veinengagement face angle 364 can be one hundred ten degrees (110°). Inanother embodiment, the vein engagement face angle 364 can be onehundred fifteen degrees (115°).

In still yet another embodiment, the vein engagement face angle 364 canbe one hundred twenty degrees (120°). In another embodiment, the veinengagement face angle 364 can be one hundred twenty five degrees (125°).In yet another embodiment, the vein engagement face angle 364 can be onehundred thirty degrees (130°). In another embodiment, the veinengagement face angle 364 can be one hundred thirty five degrees (135°).In another embodiment, the vein engagement face angle 364 can be onehundred forty degrees (140°). In another embodiment, the vein engagementface angle 364 can be one hundred forty five degrees (145°). In anotherembodiment, the vein engagement face angle 364 can be one hundred fiftydegrees (150°).

As depicted in FIG. 7, the distal end 358 of each straight leg 350, 352,354 can be enlarged. For example, the distal end 358 of each straightleg 350, 352, 354 can be generally spade-shaped. In a particularembodiment, a width of the distal end 358 is at least one and one-halftimes (1.5×) greater than a diameter of the straight leg 350, 352, 354.In another embodiment, the width of the distal end 358 is at least twotimes (2×) greater than the diameter of the straight leg 350, 352, 354.In yet another embodiment, the width of the distal end 358 is at leasttwo and one-half times (2.5×) greater than the diameter of the straightleg 350, 352, 354. In still another embodiment, the width of the distalend 358 is at least three times (3×) greater than the diameter of thestraight leg 350, 352, 354. The width of the distal end 358 of eachstraight leg 350, 352, 354 is not greater than the outer diameter of thehead 302 of the embolic filter 300.

Enlarging the distal end 358 of each straight leg 350, 352, 354 canallow the vein engagement face 360 to be enlarged which can increase theengagement of the vein engagement face 360 with the vein in which theembolic filter 300 is installed. However, the distal end 358 of eachstraight leg 350, 352, 354 can have the same diameter as the straightleg 350, 352, 354.

In a particular embodiment, the vein engagement face 360 can beroughened. For example, the roughening process can include acid etching;application of a bead coating, e.g., cobalt chrome beads; application ofa roughening spray, e.g., titanium plasma spray (TPS); laser blasting;or any other similar process or method. Roughening the vein engagementface 360 can increase the engagement of the vein engagement face 360with the inner wall of the vein in which the embolic filter isinstalled. The vein engagement face 360 of each straight leg 350, 352,354 can substantially prevent caudal migration of the embolic filter300. In other words, the vein engagement face 360 can engage the innerwall of the vein and substantially prevent the embolic filter 300 frommoving downstream in a caudal direction within the vein.

Each bent arm 308, 310, 312, 314, 316, 318 can include a bent armlength. Further, each bent leg 330, 332, 334 can include a bent leglength. Moreover, each straight leg 350, 352, 354 can include a straightleg length. In a particular embodiment, the bent arm length isapproximately six-tenths times (0.6×) the bent leg length. In anotherembodiment, the bent arm length is approximately six and one-half tenthstimes (0.65×) the bent leg length. In yet another embodiment, the bentarm length is approximately seven-tenths times (0.7×) the bent leglength. In still another embodiment, the bent arm length isapproximately seven and one-half tenths times (0.75×) the bent leglength. In another embodiment, the bent arm length is approximatelyeight tenths times (0.8×) the bent leg length.

In a particular embodiment, the straight leg length is approximatelyninety-five one hundreds times (0.95×) the bent leg length. In anotherembodiment, the straight leg length is approximately ninety-six onehundreds times (0.96×) the bent leg length. In yet another embodiment,the straight leg length is approximately ninety-seven one hundreds times(0.97×) the bent leg length. In still another embodiment, the straightleg length is approximately ninety-eight one hundreds times (0.98×) thebent leg length. In another embodiment, the straight leg length isapproximately ninety-nine one hundreds times (0.99×) the bent leglength. In yet another embodiment, the straight leg length isapproximately equal to the bent leg length.

During installation and deployment, the vein engagement face 360 of eachstraight leg 350, 352, 354 can allow the embolic filter 300 to move in acranial direction. As such, the embolic filter 300 can be moved in thecranial direction to allow the bent legs 330, 332, 334, e.g., the feet344 thereof, to engage the inner wall of the vein. The straight legs350, 352, 354, however, can prevent the embolic filter 300 from movingcaudally and allowing the feet 344 of the bent legs 330, 332, 334 todisengage from the inner wall of the vein. As such, the embolic filter300 can be substantially locked and place within the vein and theembolic filter 300 can be prevented from moving cranially or caudallywithin the vein. In a particular embodiment, cranial migration is towarda patient's head and caudal migration is longitudinally opposite thecranial migration, i.e., toward a patient's lower end.

Referring now to FIG. 9, a cross-section view of the head 302 of theembolic filter 300 is shown. As shown, each bent arm 308, 310, 312, 314,316, 318 can have a bent arm diameter 902. In a particular embodiment,the bent arm diameter 902 can be in a range of ten thousands of an inchto fifteen thousands of an inch (0.010″-0.015″). Each bent leg 330, 332,334 can have a bent leg diameter 904. The bent leg diameter 904 can bein a range of ten thousands of an inch to fifteen thousands of an inch(0.010″-0.015″). Each straight leg 350, 352, 354 can have a straight legdiameter 906. The straight leg diameter 906 can be in a range ofeighteen thousands of an inch to thirty thousands of an inch(0.018″-0.030″). As such, each straight leg 350, 352, 354 can have astiffness that is greater than a stiffness of each bent leg 330, 332,334 and a stiffness of each bent arm 308, 310, 312, 314, 316, 318.

A ratio of the bent arm diameter 902 to the straight leg diameter 906 isin a range of 0.33 to 0.83. Also, a ratio of the bent leg diameter 904to the straight leg diameter 906 is in a range of 0.33 to 0.83. Stateddifferently, the straight leg diameter 906 is at least one andtwo-tenths times (1.2×) greater than the bent leg diameter 904, or thebent arm diameter 902. Further, in the straight leg diameter 906 is notgreater than three times (3×) greater than the bent leg diameter 904, orthe bent arm diameter 902. The relatively larger diameter can provideadditional stiffness that is desirable to prevent caudal migration. Forexample, the increased stiffness of the straight legs 350, 352, 354 cancause the straight legs 350, 352, 354 to splay radially outward andprovide an outward force to maintain the vein engagement face 360 ofeach straight leg 350, 352, 354 in contact with the inner wall of thevein in which the embolic filter 300 is installed. Accordingly, thestiffer legs can decrease the likelihood of caudal migration of theembolic filter 300.

The cross-section view shows a first arrangement of the arms 308, 310,312, 314, 316, 318 and legs 330, 332, 334, 350, 352, 354 within the head302 of the embolic filter 300. In order to minimize the invasion of thepatient during the installation of the embolic filter 300, it may bedesirable to minimize the outer diameter of the head 302 of the embolicfilter 300. Minimizing the outer diameter can result in a minimizedinternal diameter of the embolic filter 300. In order to fit within thehead 302, the arms 308, 310, 312, 314, 316, 318 and legs 330, 332, 334,350, 352, 354 can be arranged as shown in FIG. 9. In a particularembodiment, when collapsed, the embolic filter can be installed using aseven French catheter. In another embodiment, the embolic filter can beinstalled using a six French catheter. In still another embodiment, theembolic filter can be installed using a five French catheter.

For example, the bent legs 330, 332, 334, e.g., the proximal endsthereof, can be arranged around the center of the head, e.g., the pointthrough which the longitudinal axis (not shown in FIG. 9) of the embolicfilter 300 passes, so that the centers of the bent legs 330, 332, 334form an equilateral triangle. Further, the proximal end of the firststraight leg 350 can be placed in contact with the proximal end of thefirst bent leg 330 and the proximal end of the second bent leg 332. Theproximal end of the second straight leg 352 can be placed in contactwith the proximal end of the second bent leg 332 and the proximal end ofthe third bent leg 334. Also, the proximal end of the third straight leg354 can be placed in contact with the proximal end of the third bent leg334 and the proximal end of the first bent leg 330. Accordingly, thecenters of the straight legs 350, 352, 354 can also form an equilateraltriangle.

Thereafter, the proximal ends of the first and second bent arms 308, 310can be placed adjacent to each other within a first space 912 bound bythe first straight leg 350, the second bent leg 332 and the secondstraight leg 352. The proximal ends of the third and fourth bent arms312, 314 can be placed adjacent to each other within a second space 914bound by the second straight leg 352, the third bent leg 334 and thethird straight leg 354. Moreover, the proximal ends of the fifth andsixth bent arms 316, 318 can be placed adjacent to each other within athird space 916 bound by the third straight leg 354, the first bent leg330 and the first straight leg 334.

Referring to FIG. 10, an alternative arrangement of the arms 308, 310,312, 314, 316, 318 and legs 330, 332, 334, 350, 352, 354 within the head302 is shown. FIG. 10 shows that the proximal ends of the straight legs350, 352, 354 can be arranged around the center of the head, e.g., thepoint through which the longitudinal axis (not shown in FIG. 10) of theembolic filter 300 passes, so that the centers of the straight legs 350,352, 354 form an equilateral triangle.

The proximal end of the first bent leg 330 can be placed in contact withthe proximal end of the first straight leg 350 and the proximal end ofthe second straight leg 352. The proximal end of the second bent leg 332can be placed in contact with the proximal end of the second straightleg 352 and the proximal end of the third straight leg 354. Further, theproximal end of the third bent leg 334 can be placed in contact with theproximal end of the third straight leg 354 and the proximal end of thefirst straight leg 350. As such, the centers of the bent legs 330, 332,334 also form an equilateral triangle. Further, the proximal end of thefirst straight leg 350 can be placed in contact with the proximal end ofthe first bent leg 330 and the proximal end of the second bent leg 332.The proximal end of the second straight leg 352 can be placed in contactwith the proximal end of the second bent leg 332 and the proximal end ofthe third bent leg 334. Also, the proximal end of the third straight leg354 can be placed in contact with the proximal end of the third bent leg334 and the proximal end of the first bent leg 330.

Thereafter, the proximal ends of the first and second bent arms 308, 310can be placed on each side of the proximal end of the first bent leg 330so that the proximal ends of the first and second bent arms 308, 310flank the proximal end of the first bent leg 330. The proximal ends ofthe third and fourth bent arms 312, 314 can be placed on each side ofthe proximal end of the second bent leg 332 so that the proximal ends ofthe third and fourth bent arms 312, 314 flank the proximal end of thesecond bent leg 332. Moreover, the proximal ends of the fifth and sixthbent arms 316, 318 can be placed on each side of the proximal end of thethird bent leg 334 so that the proximal ends of the fifth and sixth bentarms 316, 318 flank the proximal end of the third bent leg 334.

CONCLUSION

With the configuration of structure described above, one or more of theembodiments described herein can provide a device that can bepermanently or temporarily installed within a patient, e.g., within aninferior vena cava of a patient. The embodiments described herein caninclude a plurality of bent arms that provide lateral stability andmaintain the embolic filter substantially centered within the inferiorvena cava. Further, features of the embodiments described herein caninclude a plurality of bent legs that extend in generally the samedirection as the bent arms. Each bent leg can include a foot that can beformed with a hook or a barb. The feet of the bent legs can engage theinner wall of the inferior vena cava and can substantially preventcranial migration of the embolic filter.

Moreover, the embodiments described herein can include a plurality ofstraight legs. Each straight leg can include a vein engagement face thatcan engage the inferior vena cava in a direction opposite the feet ofthe bent legs. The vein engagement faces can prevent caudal migration ofthe embolic filter. Accordingly, when the embolic filter is placedwithin the inferior vena cava it can remain substantially within theoriginal location in which it is placed until it is removed.

The embolic filter, as described herein, includes six arms and six legs.It can be appreciated that the embolic filter can include more or lessthan six arms and more or less than six legs. Further, the embolicfilter, as described herein, includes three bent legs and three straightlegs. However, the embolic filter can include other combinations of bentlegs and straight legs, e.g., four bent legs and two straight legs, twobent legs and four straight legs, etc. Also, the straight legs can beformed similar to the bent legs, e.g., with a bend, while retaining therelatively larger diameter. Additionally, one or more of the arms can beformed similar to the straight legs, e.g., with or without a bend, withan enlarged distal end, with a vein engagement face, or a combinationthereof.

The above-disclosed subject matter is to be considered illustrative, andnot restrictive, and the appended claims are intended to cover all suchmodifications, enhancements, and other embodiments that fall within thetrue spirit and scope of the present invention. Thus, to the maximumextent allowed by law, the scope of the present invention is to bedetermined by the broadest permissible interpretation of the followingclaims and their equivalents, and shall not be restricted or limited bythe foregoing detailed description.

What is claimed is:
 1. An embolic filter, comprising: a) a head having aproximal end and a distal end; b) a plurality of appendages extendingdistally from the head distal end including a plurality of arms, a firstplurality of legs that are longer than the arms, the first plurality oflegs including a plurality of bent legs, wherein each bent leg has a legdistal end providing a curved anchor with a curved portion, said curvedanchor configured to engage an inner wall of a vein and prevent theembolic filter from migrating in a cranial direction, each bent leghaving a bend that is positioned in between the leg curved anchor andthe head, so that the curved anchor is not the location of the bend; c)a second plurality of legs that are longer than the arms and including aplurality of straight legs extending from the head, wherein eachstraight leg has a distal end with a caudal anchor that is configured toengage an inner wall of a vein to prevent the embolic filter frommigrating in a caudal direction; and d) wherein the curved anchor of thebent legs is of a different configuration as compared to the caudalanchor of the straight legs.
 2. The embolic filter of claim 1, whereinsome of the arms are bent.
 3. The embolic filter of claim 1, wherein thecaudal anchor at the distal end of each straight leg is tapered toprovide a smaller end portion spaced away from the head and to provide avein engagement surface that is configured to engage an inner wall of avein and prevent the embolic filter from migrating in a caudaldirection.
 4. The embolic filter of claim 3, wherein each straight legdefines a longitudinal axis, and the distal end of each of the pluralityof straight legs includes a caudal anchor with a vein engagement facethat is generally planar and angled relative to the straight leglongitudinal axis, thus configured to engage an inner wall of a vein andprevent the embolic filter from migrating in a caudal direction.
 5. Theembolic filter of claim 4, wherein each vein engagement face is angledwith respect to the longitudinal axis of each straight leg to define avein engagement face angle that is an obtuse angle.
 6. The embolicfilter of claim 3, wherein the head has a central longitudinal axis andsaid vein engagement surface being generally aligned with the centrallongitudinal axis of the head.
 7. The embolic filter of claim 1 whereinthe head has a longitudinal axis and there is a primary bent arm angleof between about 45 and 65 degrees between each bent arm and saidlongitudinal axis.
 8. The embolic filter of claim 1 wherein the head hasa longitudinal axis and each bent leg forms an angle of between about 20degrees and 45 degrees with said longitudinal axis.
 9. The embolicfilter of claim 1 wherein each bent leg has a secondary bend angle ofbetween about 5 and 25 degrees.
 10. The embolic filter of claim 1wherein the head has a longitudinal axis and each straight leg forms anangle of between about 20 and 45 degrees with said longitudinal axis.11. Apparatus including the embolic filter of claim 1 and a filterdelivery system that includes a catheter and wherein when the embolicfilter is in a collapsed position within the catheter, the arms and thelegs extend in one direction from the head.
 12. The embolic filter ofclaim 1 wherein the head has a central longitudinal axis, the benddivides the bent leg into proximal and distal sections, the proximalsection forming a first acute angle with the head axis, the distalsection forming a second acute angle with the head axis that is largerthan the first angle.
 13. An embolic filter, comprising: a) a headhaving a proximal end, a distal end, and a head central longitudinalaxis; b) a first plurality of legs extending from the head distal end,wherein each of the first plurality of legs has a curved distal anchorthat is configured to curve away from said head central longitudinalaxis and engage an inner wall of a vein and prevent the embolic filterfrom migrating in a cranial direction and wherein each of the firstplurality of legs has a first leg diameter; c) a second plurality oflegs extending from the head, wherein each of the second plurality oflegs has a leg axis and a distal end with a caudal anchor that includesan angled face that is configured to prevent the embolic filter frommigrating in a caudal direction and wherein each of the second pluralityof legs has a second leg diameter that is at least 1.2 times greaterthan the first leg diameter; and d) wherein the angled face and the legaxis form an angle that is not a right angle; and e) a plurality of armsextending away from the head, wherein each of said arms is shorter thaneach of said legs.
 14. The embolic filter of claim 13, wherein thesecond leg diameter is at most 3 times greater than the first legdiameter.
 15. The embolic filter of claim 14, wherein the distal endangled face of the caudal anchor is configured to engage an inner wallof a vein with a surface that forms an angle with the leg longitudinalaxis and wherein the surface is generally aligned with the inner wall ofthe vein when the filter is deployed in the vein, said surfacepreventing the embolic filter from moving in a caudal direction withinthe vein.
 16. The embolic filter of claim 15, wherein the distal end ofeach of the second plurality of legs has a width that is at least oneand one-half times (1.5×) greater than the second leg diameter.
 17. Theembolic filter of claim 15, wherein the caudal anchor at the distal endof each of the second plurality of legs includes a vein engagement facethat is configured to engage an inner wall of a vein and prevent theembolic filter from moving in a caudal direction within the vein. 18.The embolic filter of claim 17, wherein each vein engagement face isroughened using a roughening process.
 19. Apparatus including theembolic filter of claim 13 and a filter delivery system that includes acatheter and wherein when the embolic filter is in a collapsed positionwithin the catheter, the arms and the legs extend in one direction fromthe head.
 20. The embolic filter of claim 13, wherein the distal end ofeach straight leg is tapered to provide a surface that is configured toengage an inner wall of a vein and prevent the embolic filter frommigrating in a caudal direction, said surface being generally alignedwith the central longitudinal axis of the head.
 21. An embolic filter,comprising: a) a head having a proximal end and a distal end; b) a firstbent arm, a second bent arm, a third bent arm, a fourth bent arm, afifth bent arm, and a sixth bent arm extending distally from the headdistal end, wherein each bent arm has an arm length and includes aproximal end and a bent arm diameter; c) a first bent leg, a second bentleg, and a third bent leg extending from the head distal end, whereineach bent leg includes a proximal end and a bent leg diameter that issubstantially equal to the bent arm diameter, each bent leg being longerthan at least some bent arms; d) a first straight leg, a second straightleg, and a third straight leg extending from the head distal end,wherein each straight leg has a proximal end and a straight leg diameterthat is at least 1.2 times greater than the bent leg diameter or thebent arm diameter, each straight leg being longer than at least somebent arms; e) a plurality of the bent legs having curved ends spacedaway from the head that define first anchors; and f) a plurality of thestraight legs having ends that are spaced away from the head that definesecond anchors; g) wherein the first anchors are of a configuration thatdiffers from the configuration of the second anchors.
 22. The embolicfilter of claim 21, wherein each bent leg includes a center and whereinthe proximal ends of the bent legs are arranged within the head so thatthe centers of the bent legs form an equilateral triangle within thehead.
 23. The embolic filter of claim 22, wherein the proximal end ofthe first straight leg is disposed within the head in contact with theproximal end of the first bent leg and the proximal end of the secondbent leg.
 24. The embolic filter of claim 23, wherein the proximal endof the second straight leg is disposed within the head in contact withthe proximal end of the second bent leg and the proximal end of thethird bent leg.
 25. The embolic filter of claim 24, wherein the proximalend of the third straight leg is disposed within the head in contactwith the proximal end of the third bent leg and the proximal end of thefirst bent leg.
 26. The embolic filter of claim 25, wherein the firststraight leg includes a center, the second straight leg includes acenter, and the third straight leg includes a center and wherein thecenters of the straight legs form an equilateral triangle within thehead.
 27. The embolic filter of claim 26, wherein the proximal end ofthe first bent arm and the proximal end of the second bent arm aredisposed within the head adjacent to each other within a first spacebound by the proximal end of the first straight leg, the proximal end ofthe second bent leg, and the proximal end of the second straight leg.28. The embolic filter of claim 27, wherein the proximal end of thethird bent arm and the proximal end of the fourth bent arm are disposedwithin the head adjacent to each other within a second space bound bythe proximal end of the second straight leg, the proximal end of thethird bent leg, and the proximal end of the third straight leg.
 29. Theembolic filter of claim 28, wherein the proximal end of the fifth bentarm and the proximal end of the sixth bent arm are disposed within thehead adjacent to each other within a third space bound by the proximalend of the third straight leg, the proximal end of the first bent leg,and the proximal end of the first straight leg.
 30. The embolic filterof claim 22 wherein the head has a generally cylindrically shaped wall,and wherein some of the legs are in contact with the wall and with oneor more other legs.
 31. The embolic filter of claim 22 wherein the headhas a generally cylindrically shaped wall, and wherein some of the legsare in contact with the wall and with one or more other arms. 32.Apparatus including the embolic filter of claim 21 and a filter deliverysystem that includes a catheter and wherein when the embolic filter isin a collapsed position within the catheter, the arms and the legsextend in one direction from the head.
 33. The embolic filter of claim21 wherein the head has a central longitudinal axis, each bent leg has adistal end and a bend in between the head and the distal end thatdivides each bent leg into proximal and distal sections, the proximalsection of each bent leg forming a first acute angle with the head axis,the distal section of each bent leg forming a second acute angle withthe head axis that is larger than the first angle.